@Nullable
 public static Set<PsiType> getExpectedTypes(final CompletionParameters parameters) {
   final PsiExpression expr =
       PsiTreeUtil.getContextOfType(parameters.getPosition(), PsiExpression.class, true);
   if (expr != null) {
     final Set<PsiType> set = new THashSet<PsiType>();
     for (final ExpectedTypeInfo expectedInfo :
         JavaSmartCompletionContributor.getExpectedTypes(parameters)) {
       set.add(expectedInfo.getType());
     }
     return set;
   }
   return null;
 }
  public static boolean insertTail(
      InsertionContext context, LookupElement item, TailType tailType, boolean hasTail) {
    TailType toInsert = tailType;
    LookupItem<?> lookupItem = item.as(LookupItem.CLASS_CONDITION_KEY);
    if (lookupItem == null
        || lookupItem.getAttribute(LookupItem.TAIL_TYPE_ATTR) != TailType.UNKNOWN) {
      if (!hasTail
          && item.getObject() instanceof PsiMethod
          && ((PsiMethod) item.getObject()).getReturnType() == PsiType.VOID) {
        PsiDocumentManager.getInstance(context.getProject()).commitAllDocuments();
        if (psiElement()
            .beforeLeaf(psiElement().withText("."))
            .accepts(context.getFile().findElementAt(context.getTailOffset() - 1))) {
          return false;
        }

        boolean insertAdditionalSemicolon = true;
        final PsiReferenceExpression referenceExpression =
            PsiTreeUtil.getTopmostParentOfType(
                context.getFile().findElementAt(context.getStartOffset()),
                PsiReferenceExpression.class);
        if (referenceExpression instanceof PsiMethodReferenceExpression
            && LambdaHighlightingUtil.insertSemicolon(referenceExpression.getParent())) {
          insertAdditionalSemicolon = false;
        } else if (referenceExpression != null) {
          PsiElement parent = referenceExpression.getParent();
          if (parent instanceof PsiMethodCallExpression) {
            parent = parent.getParent();
          }
          if (parent instanceof PsiLambdaExpression
              && !LambdaHighlightingUtil.insertSemicolonAfter((PsiLambdaExpression) parent)) {
            insertAdditionalSemicolon = false;
          }
        }
        if (insertAdditionalSemicolon) {
          toInsert = TailType.SEMICOLON;
        }
      }
    }
    toInsert.processTail(context.getEditor(), context.getTailOffset());
    return true;
  }
  public static Set<LookupElement> processJavaReference(
      PsiElement element,
      PsiJavaReference javaReference,
      ElementFilter elementFilter,
      JavaCompletionProcessor.Options options,
      final PrefixMatcher matcher,
      CompletionParameters parameters) {
    final Set<LookupElement> set = new LinkedHashSet<LookupElement>();
    final Condition<String> nameCondition =
        new Condition<String>() {
          @Override
          public boolean value(String s) {
            return matcher.prefixMatches(s);
          }
        };

    PsiMethodCallExpression call =
        PsiTreeUtil.getParentOfType(element, PsiMethodCallExpression.class);
    boolean checkInitialized =
        parameters.getInvocationCount() <= 1
            && call != null
            && PsiKeyword.SUPER.equals(call.getMethodExpression().getText());

    final JavaCompletionProcessor processor =
        new JavaCompletionProcessor(
            element, elementFilter, options.withInitialized(checkInitialized), nameCondition);
    final PsiType plainQualifier = processor.getQualifierType();
    PsiType qualifierType = plainQualifier;

    PsiType runtimeQualifier = getQualifierCastType(javaReference, parameters);
    if (runtimeQualifier != null) {
      PsiType composite =
          qualifierType == null
              ? runtimeQualifier
              : PsiIntersectionType.createIntersection(qualifierType, runtimeQualifier);
      PsiElement ctx = createContextWithXxxVariable(element, composite);
      javaReference =
          (PsiReferenceExpression)
              JavaPsiFacade.getElementFactory(element.getProject())
                  .createExpressionFromText("xxx.xxx", ctx);
      qualifierType = runtimeQualifier;
      processor.setQualifierType(qualifierType);
    }

    javaReference.processVariants(processor);

    final PsiTypeLookupItem castItem =
        runtimeQualifier == null
            ? null
            : PsiTypeLookupItem.createLookupItem(
                runtimeQualifier, (PsiReferenceExpression) javaReference);

    final boolean pkgContext = inSomePackage(element);

    final Set<PsiMember> mentioned = new THashSet<PsiMember>();
    for (CompletionElement completionElement : processor.getResults()) {
      for (LookupElement item : createLookupElements(completionElement, javaReference)) {
        item.putUserData(QUALIFIER_TYPE_ATTR, qualifierType);
        final Object o = item.getObject();
        if (o instanceof PsiClass && !isSourceLevelAccessible(element, (PsiClass) o, pkgContext)) {
          continue;
        }
        if (o instanceof PsiMember) {
          if (isInExcludedPackage((PsiMember) o, true)) {
            continue;
          }
          mentioned.add(CompletionUtil.getOriginalOrSelf((PsiMember) o));
        }
        set.add(
            highlightIfNeeded(
                qualifierType,
                castQualifier(item, castItem, plainQualifier, processor),
                o,
                element));
      }
    }

    if (javaReference instanceof PsiJavaCodeReferenceElement
        && !((PsiJavaCodeReferenceElement) javaReference).isQualified()) {
      final StaticMemberProcessor memberProcessor = new JavaStaticMemberProcessor(parameters);
      memberProcessor.processMembersOfRegisteredClasses(
          matcher,
          new PairConsumer<PsiMember, PsiClass>() {
            @Override
            public void consume(PsiMember member, PsiClass psiClass) {
              if (!mentioned.contains(member)
                  && processor.satisfies(member, ResolveState.initial())) {
                set.add(memberProcessor.createLookupElement(member, psiClass, true));
              }
            }
          });
    }

    return set;
  }